This study investigated the impact of hydrolyzed plant proteins on the physical, thermal, and rheological properties of rice flour (RF) for protein fortification for the elderly and general food systems. Faba bean protein concentrate and chickpea flour were first treated with polysaccharide hydrolyzed enzymes (control; CTFP and CTCF, respectively) and subsequentially with protease hydrolyzed enzymes (hydrolyzed protein material; HZFP and HZCF, respectively). The addition of CTFP and HZFP enhanced the swelling power of RF, whereas the CTCF and HZCF exhibited the opposite trends. Adding all controls and hydrolyzed protein materials to RF increased the solubility and gelatinization temperature and decreased the gelatinization enthalpy. The HZFP addition successfully developed the pasting viscosity of RF, whereas the others did not. The RF-HZFP mixture had a higher peak viscosity than RF but lower trough, breakdown, final, and setback viscosities. These findings suggest that the controls and hydrolyzed protein materials studied here could be used as sources for protein fortification of foods, particularly for the elderly, with minimal changes in textural and rheological characteristics, thereby contributing to the development of nutritious and palatable food products.

This study investigated the physicochemical properties of protein-fortified rice flour by mixing rice flour (RF) with untreated and fermented plant proteins. Fermented faba bean protein concentrate (FMFP) and chickpea flour (FMCF) were prepared by solid-state fermentation of faba bean protein concentrate (UTFP) and chickpea flour (UTCF) using Bacillus subtilis. FMFP and FMCF exhibited higher crude protein, reducing sugar and starch contents more than their counterparts. The increased rate of essential and branched-chain amino acids in FMFP and FMCF exceeded that of crude protein. Adding plant proteins to RF decreased swelling power (SP) and increased solubility in RF-UTFP and RF-FMFP mixtures, while SP and solubility increased in RF-UTCF and RF-FMCF mixtures. All RF-plant protein mixtures showed higher gelatinization temperature and lower gelatinization enthalpy than RF. Thermal gelation was found in all RF-plant protein mixtures, but the RF-FMCF mixture may form weak and unstable gel structures. The increase in pasting viscosity was minimal for the RF-UTFP and RF-FMFP mixtures but more pronounced for the RF-UTCF and RF-FMCF mixtures. Overall, FMFP may be a potential protein source to supplement the protein deficiency in RF with minimal changes in RF-based foods’ rheological and textural properties.